To keep a telecom network operable, services in the network and resources consumed by these services must be controlled in an accurate, timely and complete manner. Policy and charging control of service is one of the important controls to enable the operation of the telecom network.
The 3rd Generation Partnership Project (3GPP) system stipulates a Policy and Charging Control (PCC) framework, as shown in FIG. 1. A Policy and Charging Rules Function (PCRF) forms the core part of the PCC system and is configured to set a PCC rule. The PCRF sends a PCC rule to a Policy and Charging Enforcement Function (PCEF) for implementation. In addition, the PCRF need to ensure that a network control rule matches subscription data. The PCRF sets a PCC rule based on the following: service-related information obtained from an Application Function (AF), subscription-related information obtained from a Subscription Profile Repository (SPR), and information relating to a bearer network obtained from the PCEF. The PCEF is designed to perform traffic charging according to a PCC rules from the PCRF. Such charging operations can be performed online or offline. For online charging, the PCEF works with an Online Charging System (OCS) for credit management; for offline charging, the PCEF exchanges related charging information with an Offline Charging System (OFCS). Moreover, the PCEF is usually located on a network gateway (GW).
A Bearer Binding and Event Report Function (BBERF) is used to execute a Quality of Service (QoS) rule. The BBERF is generally located on an IP access gateway, such as a Serving GW in a System Architecture Evolution (SAE) network or Mobile Access Gateway (MAG) in a non-3GPP network. While sending a QoS rule, the PCRF informs the BBERF of a triggering event type to indicate that the BBERF reports an event to the PCRF when a matched triggering event occurs and requests for a QoS rule. The BBERF checks service data flows according to a traffic filter defined in the rule from the PCRF and implements policy control on these service flows as required by the PCRF.
A BBERF and Gxx interface described in the preceding architecture are optional. When the BBERF and Gxx interface exist, a mobile IP tunnel is established between the network entities, where the BBERF and PCEF are located, and the network entities communicate through protocol such as Mobility IP (MIP) or Proxy Mobility IP (PMIP). In this situation, certain 3GPP-defined parameters cannot be transferred between the BBERF and PCEF through an MIP message. As there's no bearer concept in the MIP or PMIP protocol, a bearer-related event can be recognized by the BBERF but not by the PCEF. Nevertheless, the PCEF needs to perform charging control according to the bearer-related event and the BBERF also need perform policy control according to an event that occurs on the PCEF.
In the prior art, the PCRF supports information transfer between the BBERF and PCEF, which enables the forwarding of information and messages that cannot be transferred between the BBERF and PCEF through an MIP message. The BBERF and PCRF set up a gateway control session and the PCRF sends a triggering event type that requires BBERF monitoring to the BBERF and if an event report reported by the BBERF is forwarded to the PCEF via the PCRF. When detecting the occurrence of an event and the event can match the triggering event type sent from the PCRF, the BBERF will report the event report to the PCRF, which in turn forwards the event report to the PCEF through a policy and charging rule provisioning message. The PCEF and PCRF set up an IP Connectivity Access Network (IP-CAN) session and the PCRF sends a triggering event type that requires PCEF monitoring to the PCEF if an event report reported by the PCEF is forwarded to the BBERF via the PCRF. When detecting the occurrence of an event and the event can match the triggering event type sent from the PCRF, the PCEF will report the event report to the PCRF, which in turn forwards the event report to the BBER.
The prior art provides a mechanism to transfer an event report between the BBERF and PCEF via the PCRF. However, the PCEF actually do not necessarily require all event reports from the BBERF but need event reports of certain types. Similarly, the BBERF does not necessarily need all event reports from the PCEF. Nevertheless, under the prior mechanism, the PCRF forwards all event reports to the BBERF and PCEF, causing a large amount of redundant information and a waste of network signaling resources. Moreover, an operator usually deploys a small number of PCRF nodes in a network. To handle a huge amount of redundant information, the prior mechanism must consume massive PCRF resources to exchange messages between the BBERF and PCEF.